WHAT WE'RE LOOKING AT: Whether Arizona charter-school students outperformed the state average for their ethnic subgroups.

ANALYSIS: Eileen Sigmund, the president of the Arizona Charter Schools Association, tweeted in September that charter-school students in all racial and ethnic groups are outperforming the state average for those groups.

Though Sigmund’s tweet doesn’t say the claim is based on AzMERIT test scores, the association’s report from which the tweet originated is titled “Public Charter School Performance, Analyses of 2017 AzMERIT Data.”

More broadly, the association’s report states public charter school students “outperform their peers, as AzMERIT results show charter students scored better than the state average in virtually every grade level and subject area for the third straight year.”

Generally, charter school students have performed well on the tests since their introduction in the spring of 2015.

AzMERIT tests are standardized tests for students in third grade through high school. The tests cover subjects like math and English for public school students and push for Common Core standards.

The Arizona Department of Education’s AzMERIT annual assessment data is separated in four groups: schools, districts and charter holders, county and state.

The data shows performance by seven ethnicities, gender and other subgroups such as students with disabilities, migrant students, and students experiencing homelessness.

Each breaks down the the data differently. Schools gives scores and other information about how various groups of students performed on a school-by-school level. The state group shows results for all district, charter and alternative schools, and all those types of schools combined.

In all but the state grouping, information about how students in different ethnic groups performed is redacted. That's done to protect student privacy, according to the Arizona Department of Education.

The association compared the percentage passing in each of the seven ethnic subgroups in all schools and the percentage passing in just charter schools, said Ildi Laczko-Kerr, the Chief Academic Officer with the Arizona Charter School Association.

According to an analysis by AZ Fact Check, the AzMERIT test result data for the 2017, 2016, and 2015 academic school years shows charter school students in all seven ethnic and racial subgroups did outperform the state percentagefor students passing.

For example, 34 percent of Hispanic or Latino students in charter schools passed the English portion of the AzMERIT exam, whereas 28 percent of Hispanic or Latino students statewide passed the English portion.

The same goes for other demographic groups — 23 percent of Native American students in charter schools passed the math portion of the AzMERIT exam, while 20 percent of Native American students statewide passed the math portion.

The charter school association didn't directly compare the data from charters against districts, because, "We actually try pretty hard not to do an us versus them," Laczko-Kerr said.

AZ Fact Check made that comparison, however, and found the “percentage passing” in each ethnic subgroup in charter schools was higher than district schools.

Matthew Chingos, the director of the Education Policy Program at the Urban Institute, called the association's comparison "meaningless."

He said comparing test scores doesn't show overall student improvement or school achievement.

“It might be the case that charter schools are getting more advantaged families, more affluent families who want a more specialized curriculum, or who have different motivations," Chingos said. "In those places, the charter schools could have higher test scores, even if they were in fact delivering a worse-quality education than traditional public schools.”

And Sherman Dorn, a professor at Arizona State University's Mary Lou Fulton Teachers College, called the claim "marketing, not research."

Dorn said the association is technically right, but that the numbers don't convey a "school's effectiveness."

Charter officials stand by their measurement.

"All students regardless of their poverty status, are included (in the analysis)," Laczko-Kerr said.

And Sigmund noted that under Arizona law students of all backgrounds are accepted into charter schools tuition-free, as long as the school is not at capacity.

BOTTOM LINE: Sigmund’s statement is true using the association’s methodology and the publicly available data provided by the Arizona Department of Education. Two researchers interviewed by AZ Fact Checkdid not question the methodology, but said comparing "percentage passing" figures on their own may not be enough to show overall student success.